Three Terminal Precision Standard Capacitor Calibrations

1 Page 1 NIST Special Publication 250-76 NIST MEASUREMENT SERVICES Three-Terminal Precision Standard Capacitor Calibrations at NIST ____________________________________________________________ Andrew Koffman Yicheng Wang Scott Sh... Open at page → 2 Page 2 Table of Contents List of Figures ………………………………………………………………...…………………. ii List of Tables ………………………………………………………………...………...………. iii 1. INTRODUCTION ……………………………………………………………………………. 1 2. REFERENCE CHARACTERIZATION ……………………………... Open at page → 3 Page 3 Figure 10. Photograph of fused-silica standard capacitor enclosures without temperature readouts. Right enclosure contains SPRT. Figure 11. Photograph of fused-silica standard capacitor enclosures with temperature readou... Open at page → 4 Page 4 1. INTRODUCTION We have recently made improvements in capacitance measurements by expanding the frequency range of and lowering the uncertainty assigned to three-terminal (3T) fused-silica and nitrogen gas dielectric sta... Open at page → 5 Page 5 value and measured value of the reference at each required frequency is used to correct the measured value of the customer standard. Fig. 2 shows the traceability chain for NIST 3T nitrogen gas and fused-silica standard... Open at page → 6 Page 6 both the high and low sides of the bridge. This effect will change with frequency according to the square of the frequency [1, 2] and so the effect on measured capacitance due to bridge loading will decrease dramatically... Open at page → 7 Page 7 Since the frequency dependences of the reference standard capacitors have been determined and straightforward measurements can provide corrections for the loading effects of capacitors on the automatic capacitance bridge... Open at page → 8 Page 8 not performed if the temperature has varied from the laboratory set point of 23.0 ºC by more than 0.5 ºC or if relative humidity has increased above 50 % within the last 72 hours. Typical commercial fused-silica standard... Open at page → 9 Page 9 DUT, the capacitance bridge thermal, mechanical, and linearity components, and the bridge loading component (see Tables 2, 3, 4, 5, 6, and 7). The 1000 pF nitrogen gas standard capacitor calibration uncertainty budget al... Open at page → 10 Page 10 capacitance bridge accuracy for 1 pF, 10 pF, 100 pF, and 1000 pF measurements is included in the Appendix. The expanded uncertainty for all calibrations is the combined standard uncertainty of the calibrated value multip... Open at page → 11 Page 11 point. The fee for having a standard capacitor calibrated at all three frequencies mentioned ab was approximately three times the fee for only one frequency. The work done to expand and automate the standard capacitor ca... Open at page → 12 Page 12 [4] Cutkosky, R. D. and Lee, L. H., “Improved ten-picofarad fused silica dielectric capacitor,” ] A.-M. Jeffery and A.D. Koffman, "Improved 1 kHz capacitance calibration uncertainty," ] Andeen-Hagerling, Inc., “AH2700A 5... Open at page → 13 Page 13 APPENDICES A. REPORT OF CALIBRATION for a 100 pF fused-silica standard capacitor under NIST test ID 52130C/52131C B. REPORT OF CALIBRATION for a 1000 pF nitrogen gas standard capacitor under NIST test ID 52140C/52141C C.... Open at page → 14 Page 14 Test Report No.: 817/275555-06 1of 3 Reference: 7654321 Date: July 31, 2006 Telephone Contact: 301-975-4221 APPENDIX A REPORT OF CALIBRATION Standard Capacitor Andeen-Hagerling, Inc., Model AH11A Serial Number 01234 AH11... Open at page → 15 Page 15 Andeen-Hagerling, Inc. Model AH11A, Serial No. 01234 Model AH1100, Serial No. 00068 Table 2. Test results Frequency (kHz ± 0.01 %) Capacitance (pF) Type A Uncertainty (μF/F) Expanded Uncertainty (μF/F) (k=2) 0.05 100.000... Open at page → 16 Page 16 Andeen-Hagerling, Inc. Model AH11A, Serial No. 01234 Model AH1100, Serial No. 00068 For standards with an air bath temperature well, the temperature at measurement is taken using a platinum resistance thermometer placed... Open at page → 17 Page 17 Test Report No.: 817/275555-06 1of 2 Reference: 7654321 Date: July 31, 2006 Telephone Contact: 301-975-4221 APPENDIX B REPORT OF CALIBRATION Standard Capacitor General Radio Company, Model 1404-A Serial Number 2316 Submi... Open at page → 18 Page 18 General Radio Company Model 1404-B, Serial No. 517 Fact Sheet: NIST Measurement of Nitrogen Dielectric Standard Capacitors Representation of the Unit of Capacitance As a result of the absolute measurements of the farad i... Open at page → 19 Page 19 Test Report No.: 817/275556-06 1 of 2 Reference: ABC123 Date: July 31, 2006 Telephone Contact: 301-975-4221 APPENDIX C REPORT OF CALIBRATION Standard Capacitor General Radio Company, Model 1404-B Serial Number 517 Submit... Open at page → 20 Page 20 Fact Sheet: NIST Measurement of Nitrogen Dielectric Standard Capacitors Representation of the Unit of Capacitance As a result of the absolute measurements of the farad in terms of the units of length and time, the legal... Open at page → 21 Page 21 APPENDIX D AH2700A Capacitance Bridge Accuracy for 1 pF, 10 pF, 100 pF, and 1000 pF Standards ‡ Fre quency 1 pF 10 pF 100 pF 1000 pF (Hz) Bridge Accuracy Bridge Accuracy Bridge Accuracy Bridge Accuracy ( μF/F) ( μF/F) (... Open at page → 22 Page 22 APPENDIX E Calibration procedure for three-terminal fused-silica standard capacitors Arrival of Standards Standards arrive at the division shipping room. The division shipping specialist documents any issues involving un... Open at page → 23 Page 23 Fused-silica standard capacitors can be calibrated at the following frequencies (listed in Hertz): 50, 80, 100, 160, 200, 300, 400, 600, 800, 1000, 1600, 2000, 3000, 4000, 6000, 8000, 10000, 12000, 16000, and 20000. Refe... Open at page → 24 Page 24 Enter the data into a spreadsheet file following the templates in the directory C:\calibrations\AHData and store the spreadsheet in the directory C:\calibrations\AHData\FusedSilicaResults\cModel_ Customer_ SerialNumber_M... Open at page → 25 Page 25 APPENDIX F Calibration procedure for high-accuracy three-terminal nitrogen gas standard capacitors Arrival of Standards Standards arrive at the division shipping room. The division shipping specialist documents any issue... Open at page → 26 Page 26 Technical Procedures Calibration of three-terminal nitrogen gas standard capacitors is performed using an AH2700A automatic capacitance bridge. A calibration consists of the mean of at least five separate capacitance mea... Open at page → 27 Page 27 All calibration files are backed up in the group directory G:\adk\calibrations following the same directory and filename patterns as above. This director y is located on a network server and is regularly backed up. Open at page → 28 Page 28 APPENDIX G Calibration procedure for low-accuracy three-terminal nitrogen gas standard capacitors Arrival of Standards Standards arrive at the division shipping room. The division shipping specialist documents any issues... Open at page → 29 Page 29 Technical Procedures Low-accuracy calibration of three-terminal nitrogen gas standard capacitors is performed using an AH2700A automatic capacitance bridge. A calibration consists of the mean of at least two separate cap... Open at page → 30 Page 30 All calibration files are backed up in the group directory G:\adk\calibrations following the same directory and filename patterns as above. This director y is located on a network server and is regularly backed up. Open at page → 31 Page 31 1 2 CbCa 3 4 Fi g. 1. Four-rod cross capacitor. Dashed line represents a ground shield. Calculable Capacitor 0.5 pF, 1592 Hz Uncertainty 0.019 μF/F Fig. 2. NIST nitrogen gas and fused-silica standard capacitor traceabili... Open at page → 32 Page 32 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 02000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Frequency Dependence (uF/F) 100 pF 10 pF 1 pF Fig. 3. Frequency dependence of 100 pF, 10 pF, and 1 pF calibra... Open at page → 33 Page 33 -0.2 0 0.2 0.4 0.6 0.8 1 0200 400 600 800 1000 1200 1400 1600 1800 2000 Frequency (Hz) Frequency Dependence (uF/F) 100 pF 10 pF 1 pF Fig. 4. Low-frequency plot of frequency dependence curves in Fig. 3. Open at page → 34 Page 34 High Low Fig. 5. Measurement of three-termin al standard capacitor using automatic capacitance bridge. B A Automatic Capacitance Bridge C LG Standard Capacitor C LH C HG Open at page → 35 Page 35 99.998 100.000 100.002 100.004 100.006 100.008 100.010 100.012 100.014 100.016 100.018 0.00.51.01.52.02.53.0 Loading Capacitance (nF) C272 Low-High Capacitance (pF) Loading at Point A (High) Loading at Point B (Low) Fig.... Open at page → 36 Page 36 9.9995 10.0000 10.0005 10.0010 10.0015 10.0020 10.0025 00.511.522.53 Loading Capacitance (nF) C172 High-Low Capacitance (pF) Loading at Point A (High) Loading at Point B (Low) Fig. 7. Bridge loading effects for 10 pF fus... Open at page → 37 Page 37 1.0000 1.0001 1.0002 1.0003 1.0004 1.0005 1.0006 1.0007 1.0008 1.0009 0.00.51.01.52.02.53.0 Loading Capacitance (nF) C016 Low-High Capacitance (pF) Loading at Point A (High) Loading at Point B (Low) Fig. 8. Bridge loadin... Open at page → 38 Page 38 Fig. 9. Photograph of the capacitance bridge, controlling laptop, and reference and customer fu sed-silica standard capacitors. Open at page → 39 Page 39 Fig. 10. Photograph of fused-silica standard cap acitor enclosures without temperature readouts. Right enclosure contains SPRT. Open at page → 40 Page 40 Fig. 11. Photograph of fused-silica standard capacitor enclosures with temperature readouts. Open at page → 41 Page 41 Fig. 12. Photograph of nitrogen gas standard capacitors. Open at page → 42 Page 42 99.99935 99.99940 99.99945 99.99950 99.99955 99.99960 99.99965 99.99970 99.99975 99.99980 99.99985 99.99990 99.99995 100.00000 100.00005 100.00010 100.00015 100.00020 100.00025 100.00030 100.00035 100.00040 02000 4000 60... Open at page → 43 Page 43 99.999390 99.999395 99.999400 99.999405 99.999410 99.999415 99.999420 99.999425 99.999430 99.999435 99.999440 99.999445 99.999450 99.999455 99.999460 02004006008001000 Frequency (Hz) Capacitance (pF) Fig. 14. Low-frequen... Open at page → 44 Page 44 99.9993 99.9994 99.9995 99.9996 99.9997 99.9998 99.9999 100.0000 100.0001 100.0002 100.0003 100.0004 100.0005 100.0006 02000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Capacitance (pF) Fig. 15. Lon... Open at page → 45 Page 45 -0.000150 -0.000125 -0.000100 -0.000075 -0.000050 -0.000025 0.000000 0.000025 0.000050 0.000075 0.000100 0.000125 0.000150 0.000175 0.000200 0.000225 0.000250 02000400060008000100001200014000160001800020000 Frequency (Hz... Open at page → 46 Page 46 9.99995 9.99996 9.99997 9.99998 9.99999 10.00000 10.00001 10.00002 10.00003 10.00004 10.00005 10.00006 10.00007 10.00008 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Capacitance (pF) Fig. 17.... Open at page → 47 Page 47 9.999951 9.999952 9.999953 9.999954 9.999955 9.999956 9.999957 9.999958 9.999959 9.999960 9.999961 9.999962 9.999963 02004006008001000 Frequency (Hz) Capacitance (pF) Fig. 18. Low-frequency portion of short-term stabilit... Open at page → 48 Page 48 9.99994 9.99995 9.99996 9.99997 9.99998 9.99999 10.00000 10.00001 10.00002 10.00003 10.00004 10.00005 10.00006 10.00007 10.00008 10.00009 10.00010 10.00011 10.00012 02000 4000 6000 8000 10000 12000 14000 16000 18000 2000... Open at page → 49 Page 49 -0.000040 -0.000035 -0.000030 -0.000025 -0.000020 -0.000015 -0.000010 -0.000005 0.000000 0.000005 0.000010 0.000015 0.000020 0.000025 0.000030 0.000035 0.000040 0.000045 0.000050 0.000055 0.000060 0.000065 02000400060008... Open at page → 50 Page 50 0.999975 0.999980 0.999985 0.999990 0.999995 1.000000 1.000005 1.000010 1.000015 1.000020 1.000025 1.000030 1.000035 1.000040 1.000045 1.000050 1.000055 1.000060 1.000065 1.000070 1.000075 1.000080 1.000085 02000 4000 60... Open at page → 51 Page 51 0.999978 0.999980 0.999982 0.999984 0.999986 0.999988 0.999990 0.999992 0.999994 0.999996 0.999998 1.000000 1.000002 1.000004 1.000006 1.000008 1.000010 1.000012 02004006008001000 Frequency (Hz) Capacitance (pF) Fig. 22.... Open at page → 52 Page 52 0.99998 0.99999 1.00000 1.00001 1.00002 1.00003 1.00004 1.00005 1.00006 1.00007 1.00008 1.00009 02000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Capacitance (pF) Fig. 23. Long-term stability of 1 p... Open at page → 53 Page 53 -0.000020 -0.000015 -0.000010 -0.000005 0.000000 0.000005 0.000010 0.000015 0.000020 0.000025 02000400060008000100001200014000160001800020000 Frequency (Hz) C - Cavg (pF) Fig. 24. Normalized long-term stability of 1 pF r... Open at page → 54 Page 54 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 02000400060008000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Expanded Uncertainty (k=2) (uF/F) Fig. 25. Expanded uncertainty (k=2) for 100 pF 3T fused-silica st... Open at page → 55 Page 55 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0200040006000800010000 12000 14000 16000 18000 20000 Frequency (Hz) Expanded Uncertainty (k=2) (uF/F) Fig. 26. Expanded uncertainty (k=2) for 10 pF 3T fused-silica standard capacit... Open at page → 56 Page 56 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 02000400060008000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Expanded Uncertainty (k=2) (uF/F) Fig. 27. Expanded uncertainty (k=2) for 1 pF 3T fused-silica standar... Open at page → 57 Page 57 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 02000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Expanded Uncertainty (k=2) (uF/F) Fig. 28. Expanded uncertainty (k=2) for 1000 pF 3... Open at page → 58 Page 58 1 2 3 4 5 6 7 8 9 10 02000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Expanded Uncertainty (k=2) (uF/F) Fig. 29. Expanded uncertainty (k=2) for 100 pF 3T nitrogen gas standard capacitor calibration... Open at page → 59 Page 59 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 02000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Frequency (Hz) Expanded Uncertainty (k=2) (uF/F) Fig. 30. Expanded uncertainty (k=2) for 10 pF 3T n... Open at page → 60 Page 60 Frequency 100 pF Reference 10 pF Reference 1 pF Reference (Hz) (272) Frequency (172) Frequency (016) Frequency Dependence (μF/F) Dependence (μF/F) Dependence (μF/F) 50 0.08 0.95 0.73 80 0.07 0.85 0.33 100 0.05 0.73 0.18... Open at page → 61 Page 61 Frequency Reference Reference Type A DUT Bridge Bridge Bridge Bridge Expanded (Hz) Uncertainty Drift (C272) Uncertainty Drift Thermal Mechanical Linearity Loading Uncertainty C272 (μF/F) (μF/F) (μF/F) (μF/F) (μF/F) (μF/F... Open at page → 62 Page 62 Frequency Reference Reference Type A DUT Bridge Bridge Bridge Bridge Expanded (Hz) Uncertainty Drift (C172) Uncertainty Drift Thermal Mechanical Linearity Loading Uncertainty C172 (μF/F) (μF/F) (μF/F) (μF/F) (μF/F) (μF/F... Open at page → 63 Page 63 Frequency Reference Reference Type A DUT Bridge Bridge Bridge Bridge Expanded (Hz) Uncertainty Drift (C016) Uncertainty Drift Thermal Mechanical Linearity Loading Uncertainty C016 (μF/F) (μF/F) (μF/F) (μF/F) (μF/F) (μF/F... Open at page → 64 Page 64 Frequency Reference Reference 10:1 Ratio Type A DUT Bridge Bridge Bridge Bridge Expanded (Hz) Uncertainty Drift (C272) UncertaintyUncertaintyDrift Thermal Mechanical LinearityLoading Uncertainty C272 (μF/F) (μF/F) (μF/F)... Open at page → 65 Page 65 Frequency Reference Reference Type A DUT Bridge Bridge Bridge Bridge Expanded (Hz) Uncertainty Drift (C272) Uncertainty Drift Thermal Mechanical Linearity Loading Uncertainty C272 (μF/F) (μF/F) (μF/F) (μF/F) (μF/F) (μF/F... Open at page → 66 Page 66 Frequency Reference Reference Type A DUT Bridge Bridge Bridge Bridge Expanded (Hz) Uncertainty Drift (C172) Uncertainty Drift Thermal Mechanical Linearity Loading Uncertainty C172 (μF/F) (μF/F) (μF/F) (μF/F) (μF/F) (μF/F... Open at page →